1. Field of the Invention
The present invention relates to a pull rope shortening device for fire extinguishing units, particularly for kitchen exhaust hoods. The device includes a shortening element which deflects the pull rope which is under tension in order to shorten the length of the pull rope, wherein the shortening element is held in the position in which it shortens the length of the pull rope by a thermally released separating device.
2. Description of the Related Art
Pull rope shortening devices of the above-described type are known, for example, for holding and securing the pull ropes of kitchen exhaust hoods. The pull ropes end at a switching device which includes a locking valve for the fire extinguishing medium. In case of fire, the thermally released element, for example, a glass bulb, of the separating device is destroyed, so that the tension of the pull rod increases the length of the pull rod, the locking valve is opened and the fire extinguishing medium can reach the location of the fire.
Pull rope shortening devices known in the art frequently are constructed in such a way that the pull rope must be cut for receiving the shortening element. It has also already been proposed to construct the shortening element in the manner of a hinge, so that the pull rope no longer has to be cut for guiding and deflecting the pull rope by the hinge. However, such a hinge is a relatively complicated component and, therefore, the hinge is relatively expensive to manufacture.